Microfluidic chip capillary electrophoresis coupled with electrochemiluminescence for enantioseparation of racemic drugs using central composite design optimization.

Optimization based on central composite design (CCD) for enantioseparation of anisodamine (AN), atenolol (AT), and metoprolol (ME) in human urine was developed using a microfluidic chip-CE device. Coupling the flexible and wide working range of microfluidic chip-CE device to CCD for chiral separation of AN, AT, and ME in human urine, a total of 15 experiments is needed for the optimization procedure as compared to 75 experiments using the normal one variable at a time optimization. The optimum conditions obtained are found to be more robust as shown by the curvature effects of the interaction factors. The developed microfluidic chip-CE-ECL system with adjustable dilution ratios has been validated by satisfactory recoveries (89.5-99% for six enanotiomers) in urine sample analysis. The working range (0.3-600 µM), repeatability (3.1-4.9% RSD for peak height and 4.0-5.2% RSD for peak area), and detection limit (0.3-0.6 µM) of the method developed are found to meet the requirements for bedside monitoring of AN, AT, and ME in patients under critical conditions. In summary, the hyphenation of CCD with the microfluidic chip-CE device is shown to offer a rapid means for optimizing the working conditions on simultaneous separation of three racemic drugs using the microfluidic chip-CE device developed.

Microfluidic chip-capillary electrophoresis with dynamic multi-segment standard addition for rapidly identifying nephrolithiasis markers in urine.

A microchip-CE device was fabricated for bed-side monitoring of nephrolithiasis biomarkers in urine by incorporating on-chip continuous passive mixing and standard addition to reduce sample matrix interference, increase sample throughput and eliminate accessories for active mixing. Under optimized conditions with buffer containing 20 mM borate and 0.5 mM CTAB at pH 10.3, sample and standards injected electrokinetically at -350 V for 10 s for online mixing in a Y-merging flow microchannel prior to CE separation and UV detection at 210 nm, both inhibitors (citrate, CA) and promoters (oxalate, OA and uric acid, UA) for nephrolithiasis can be separated and determined in human urine in a single run completed within 10 min after a simple 50-fold sample dilution and filtering. Satisfactory working ranges from 0.13-40, 0.25-40 and 0.025-40 mM, LOD 2.6, 6.1 and 0.7 µM, repeatability (%RSD, n=5) for migration time 1.40, 1.43, 0.47 and peak area 4.46, 6.10, 1.98, respectively, for CA, OA and UA are obtained for urine samples. The use of on-chip standard addition is shown to improve repeatability of the migration time, assist the identification of nephrolithiasis markers from difficult samples with noisy baseline and enlarge the working range for nephrolithiasis marker determination. The device developed can be used for both routine and emergency monitoring to deliver results on demand for bedside monitoring and public health protection. It provides an early detection of nephrolithiasis to enable timely treatments, ease anxiety of parents for neonates consuming suspected contaminated food, and quick results for patients in a critical condition.

Microfluidic chip-capillary electrophoresis for two orders extension of adjustable upper working range for profiling of inorganic and organic anions in urine.

To meet the need for onsite monitoring of urine anions, a microfluidic chip-capillary electrophoresis device was designed, fabricated and tested to extend the upper CE working range for an enhancement up to 500 fold (100 fold for sample dilution and 5 folds for CE injection) in order to analyze highly variable anionic metabolites in urine samples. Capillaries were embedded between two PMMA plates with laser-fabricated microchannel patterns to produce the microfluidic chip-capillary electrophoresis to perform standard/sample dilution and CE injection with adjustable dilution ratios. A circular ferrofluid valve was incorporated on-chip to perform cleanup and conditioning, mixing and dilution, injection and CE separation. Under optimized conditions, a complete assay for four samples can be achieved within an hour for 15 anions commonly found in urines. Satisfactory working ranges (0.005-500 mM) and low detection limits (0.5-6.5 µM based on S/N =2) are obtained with satisfactory repeatability (RSD, n=5) 0.52-0.87% and 4.1-6.5% for migration time and peak area, respectively. The working ranges with two orders adjustable upper extension are adequate to cover all analytes concentrations commonly found in human urine samples. The device fabricated shows sufficiently large experimentally verifiable enhancement factor to meet the application requirements. Its reliability was established by more than 94% recoveries of spiked standards and agreeable results from parallel method comparison with conventional ion chromatography method. The extension of the upper CE working range enables flexible onsite dilution on demand, a quick turn-around of results, and a low-cost device suitable for bedside monitoring of patients under critical conditions for metabolic disorders.

Hedyotis diffusa plus Scutellaria barbata Induce Bladder Cancer Cell Apoptosis by Inhibiting Akt Signaling Pathway through Downregulating miR-155 Expression.

Traditional Chinese medicine is increasingly used to treat cancer. Our clinical experiences identify Hedyotis diffusa plus Scutellaria barbata as the most common herb-pair (couplet medicinal) used for the core treatment of bladder cancer. This study aims to investigate the antitumor effect of the herb-pair in bladder cancer cells. The results show that Hedyotis diffusa plus Scutellaria barbata inhibited bladder cancer cell growth and clone formation in a dose-dependent and time-dependent manner. It also induced cell apoptosis through decreasing Akt activation and reducing the expression of antiapoptotic proteins Bcl-2 and Mcl-1. Further experiments showed that miR-155 was reduced by the herb-pair and miRNA-155 inhibitor induced cell apoptosis and suppressed Akt activation. Overexpression of miR-155 reversed herb-pair induced cell apoptosis through activating Akt pathway in both bladder cancer cell lines. The findings reveal that Hedyotis diffusa plus Scutellaria barbata reduce Akt activation through reducing miR-155 expression, resulting in cell apoptosis. It demonstrated the potential mechanism of Hedyotis diffusa plus Scutellaria barbata for the core treatment of bladder cancer.

Clinical laboratories on a chip for human immunodeficiency virus assay.

Automated chip-based technologies for clinical diagnosis may have great facilities in the area of life science and medicine. This paper presents the lab-on-a-chip design for the assay of HIV, which includes the sample preparation, reaction, and signal amplification module. A laser induced fluorescence system is also designed for real-time monitor of the signals.